Brake-operating mechanism



'M. B. JACKSON 1,774,796 yBRAKE OPERATING MECHANISM Y. y

v2 Sheets-Shea# 1 vFiled April 17, 1929 se zo 0 ATTORNEYS.

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Sept 2, 1930- v Mv B. JACKSON .l 1,774,796

BRAKE OPERATING MECHANISM Filed April 17, 1929 Sheets-Sheet `2 ATTORNEY.

l Patented Sept. 2, 1930 MAUNSELL BOWERS JACKSON, `01'1 TORONTO, ONTARIO, CANADA BRAKE-OPERATING MECHANISM 7 l Application. med April 17,

. This invention relates to brake operating mechanism and has for .its object to provide improved mechanism of this kind.

According to one form of the present in-v vention the mechanism includes spring means which constantly tend to apply the brakes,

and suction operated means which prevent actuation of the brakes so long as the suction operated means are connected to a source of sub-atmospheric pressure, such as the induction pipe of an internal lcombustion enine. Means are also provided for positively controlling the actuation ofthe brakes and the suction operated means, so that the brakes can be actuated to any desired extent. The invention provides a mechanism whereby the brakes of an automobile can be applied to any desired degree without undue muscular effort and where1n,should the source of suction fail, they application of the brakes can still be efected as usual and can also be released by manually applied force. The invention consi ts in the construction, combination and arrangement of parts hereinafter described and more particularly pointed out inthe ap ended claims. e Referring now to t e accompanying draw-" ings, which illustrate, by way of example', convenient forms of the invention: l Figure lis a 'side elevation of the 'preferred form of theinvention;

v. Figure 2 is an elevation of the other side A of thev device shown in Figure 1,.partly in section on'the line 2-2 of Figure 5, and with certain partsomitted;l 1

Flgure 3 '1s a transverse section on line v 3-3 of'Figure 1;

Figure .4 is a side elevation ofthe' partsK` "omitted frornFigure 2; L'

an enlarged scale;

Fi re 6 is 'a' diagrammatic. side elevation l showing the connection ofthe improved' device to an engine and brake, and

Figure 7 is a longitudinal verticalsection 'of a modified form of the invention. .7

As shown in Figures 1 to 6,' the invention comprises a horizontal cylinder 1', a rear wardl projecting casin 2 and a transverse Figure15 is a portion of Figure 3 drawn on" cylin rical portion 3, a of which mayjcon-- 1929. Serial No. 355,868.

veniently be made integral with one another. The forward end of the main cylinder 1 is closed in an air-tight manner by a plate 4. Slidably mounted 1n the cylinder 1 is a pis` ton 5 having a piston rod 6 slidably mounted 55 in the rear end wall of the cylinder, and piv,

.otally connected at its rear 4end to a lever 7 which is pivoted at 8 in the casing 2.

The lower end of lever 7 is connected by a rod9 to a brake which'is indicated at 10 in 60 Figure 6, and the lever 7 projects upwardly through a slot'll in the top of casmg 2, a

curved plate 12 being preferably provided which engages the 'top surface of casing 2 and moveswith lever 7, thus covering the slot 10 and preventing the passage of dirt through the slot regardless of the position/of lever- 7, Means constantly tending to apply the brakes are provided. These means as' illustrated comprise a spring 13 which is compressed 70 between a bracket 14 depending from the cylinder casting 1, and a disc 15 which is connected by a rod 16 to the lower end of lever 7. S ring 13 constantly tends to apply the bra e v10 andgto swing the lever-7 to the position shown in chain-dotted lines in Figure y2. A Means are provided to prevent the springl .from swinging the lever 7 except when the brake-is to be applied, and then to control pinion 21 which meshes with an arcuate rack 99 i 22 carried by an arm 23. The upper end of. arm 23 is secured to a sleeve 24 .rotatably mounted in the transversel cylinder 3. -`The sleeve 24 has an axial bore formed with. an.

internal screw thread 25 which ispreferably. 95 a multiple thread of long pitch. f

A stem 2 6 is mounted 1n the b oreof sleeve 24 and-,is formed with a thread 27 to engage the thread 25 in the sleeve.`

The `sleeve 24 is formed with ports 28 and bustion engine, indicated at 36 in Figure 6.

Acap 37 secures the member 34 to the sleeve 24 and compresses packing 38 about the pipe 35, and also restrains the sleeve against axial movement while permitting rotation thereof.

Rigidly mounted on .the outer end of valve stem 26 isa foot operated pedal 39. A spring 40 engages the pedal l39 and the arm 23 and normally maintains lan extension 41 on pedal 39, against a stop 42 on the lever 23,

the latter being normally held against a stop 43, onthe cylinder 1, by means of spring^20.

y A vent such as 46 is provided in the rear wall of the cylinder 1. Y

A vacuum tank or receiver 44 is preferably- Ainterposed in the suction pipe 35 and a suitable non-return valve, indicated at 45, may

be provided to prevent. leakage of air into -the tank when the engine is not running.

30'. constantly tends to a ply the brake but is v Y. Y normally Aprevented y cam'17 and by reduction of pressure in the The operation is as foltows': The spring 1 3 rom'doing s'o bythe cylinder 1. When the brake is to be applied,

pressure is applied to the pedal 39 which causes rotation of the valve stem 26. During the initial movement .of the pedal 39 the sleeve 24 remains stationary as spring 40 is much weaker than spring 20. The-extension" .41 therefore moves away from stop 42 and' the thread 27 causes the stem 26 and valve 30 to move axially to the right as viewed in Figures 3 and 5. This axial movement continues until the valve 30 engages its seat 33. When the valve reaches this position, the suction pipe 35 is cut off from the cylinder 1 and the latteris then in communication with the atmos here through ports 29 and 32. As atmosp eric pressure now acts on A both sides of piston 5, the spring 13 presses the lever 7 into engagementL with the cam 17,

-but the contour of the cam and the relative strengths of springs 13 and 20 are such that sprlng 13 cannot by itself cause rotation of the cam 17 against'the action of spring 20 although it has a tendency to do so.

When the valve 30 has become seated further axial movement of stem 26 is impossible andthe sleeve 24 is compelled to rotate with 'the stem 26. The rotation of the sleeve 24 causes arm 23 to be lifted from stop 43 and the consequent movement ofrack 22 causes rotation of pinion 21'against the action of spring 20.- The cam`l7 rotates with the pinion 21 in a clockwise direction as seen in Figure 2, and, since there is now atmospheric pressure on both sides of piston 5, the spring 13 expands and swings the lever 7 and thereby 'applies the brakes to a degree depending lupon the amount of movement imparted to the pedal 39. So long as the cam 17 rotates in a clockwise direction the lever 7 will remain in contact 4with the periphery of the cam, and if the pedal 39 is pressed to the limit of its movement, the narrowest part of the cam will be engaged by the lever 7 and the spring 13 Will apply the brake fully. If the movement of pedal 39 is arrested at any point between the limits of its movement, the movement of thefcam will be arrested also and the brake will` be only partially applied to a degree proportional to the movement imparted to the pedal 39.

If the operators foot is removed from the pedal 39, the spring 40 rotates it relatively to arm 23 until the extension 41 engages stop 42, and this relative rotation causes axial movement of the stem 26 to the left, as seen sov `in Figures 3 and 5. This vaxial movement disengages the valve 30 from its seat 33 to connect the cylinder 1 with the suction pipe 35 and disconnects the cylinder 1 from the atmospheric relief ports 29 and 32. The re'- duction of pressure incylinder 1 causes the piston` 5 to vpull the lever 7 'away from the cam 17 and .the same movement compresses spring 13 and takes off the brakes. The re- ;traction of lever 7 from'the cam enables the spring 20 .to return the ca'm to its normal position. If the pedal 39 is arrested before it has returned fully to its normal position,-

the spring 20 will continue to move the arm 23 until it engages the extension 41. This movement of arm 23 relative to pedal 39, ro-

tates journal 24 relatively to Athe stem 26 and returns the valve 30 to its seat 33,. thus yopening the cylinder to the atmosphere and permitting the spring 13 to pull the leverr 'A into engagement with the cam.-

It will thusbe seen that the brake will always be applied to thedesired degree, that is to a degree proportional to the movement of the pedal 39.y

When there is atmospheric pressure in the cylinder 1, the spring 13 gives the lever 7 a tendency to rotate the cam 17 against thespring 20, and the strength of the spring 13 and the contour of the cam are such that very little foot pressure'isrequired onthe pedal 39 to rotate the cam when the lever 7 is being pressed against it by the spring 13.

Accidental failure of thel suction, due to stalling of the engine or otherwise, does not cause automatic application of the brakes, but in case of such a failure the brakes can be applied by means of the pedal as above described and may be taken off by manually rocking lever 7 back to its normal position,

. lA modified form of the invention is shown in Figure 7 in which similar numerals indiiso scribed above. Instead of a cam rotated by a rack and pinion, an inclined member 17carried by a vertically slidable rodv 18 is ar ranged to be reciprocated vertically byv the forked'end of the arm 23. The spring 2O constantly urges lthe inclined member 17 towards itsy lowermost, or normal, position. The construction and operation of this formV of the invention is otherwise the sameI as in the form previously described.

The foregoing description and accompanyingdrawings are given by way-of illustration only and many'modications may be made without departing from the scope 0f the invention as defined in the following claims.

I claim: v i

1. Brake operating mechanism comprising brake lapplying means, fluid pressure operated means for rendering said brake applying means normally ineective, mechanical means for positively rendering said brake applying means ineffective, and manually operated means for actuating said mechanical means to'permit the brake applying means to become elfective to any desired degree.

2. Brake operating mechanism comprising a brake applying spring, fluid pressure operated means for rendering said 'spring normally ineective, mechanical means for positively preventing said springV from normally becoming effective, valvular means lfor controlling said fluid operated means, and manually operated means for actuating said valvular means and said mechanical means to causef said spring to become effective to a degree proportionate to the degree ofactuation'of said manually operated means.

3. Brake operating mechanism comprising brake applying spring-means, fluid pressure operated brake releasing means and manually operated means for positively controlling said brake applying andbrake releasing means in accordance with the movement of said control means.

4. Brake operating mechanism comprising.

brake applying spring means, fluid pressure operated brake releasing means, a lever connected to said brake applying -means and said brake releasing means on opposite sides of its ulcrum, mechanical means vnormally pre-v venting movement of ysaidlever, valve means for controlling said Huid pressurepperated means, and manually operable means orcontrolling said valve means and for moving said p mechanical means to permit movement of said lever 1n proportiont'o themovement of said manually operable 4means.

5. Brake operatingmechanism comprising a brake applying spring,l a chamber, a movable member in said chamber, a lever connected `to said movable member and said brake applying spring, a cam cooperating with said lever, a spring arrangedto act on said cam in oppositionto the brake applying spring, valve means to connect said chamber with either atmospheric unsub-atmospheric .pressure, and means for controlling said valve valve means to connect said chamber with subatmospheric pressure to cause compressionlof said brake applying spring or with Vatmospheric pressure to permit expansion of' Y. said brake applying springmeans to .con-

trol nsaid valve means and the movement of said cam so that the. movement of the lever is proportional to the movementof saidconl trol means. l v

. -7. Brake operating means as claimed in claim 6, wherein valve means comprises a screw-threaded stem. a valve on said stem, a sleevein which said stem is mounted, and

- wherein said control means comprises a pedal connected to said stem, an arm connected to said sleeve, and a driving connection between said arm and the cam.

8. Brake operating means -as claimed in claim- 6, wherein valve means comprisesl a screw-threaded stem. a valve on said stem, a

sleeve in which said stem` is mounted,'and

wherein said control means comprises a pedal connected to said stem, an arm connected to,

said sleeve, and a driving connection between said armv andthe cam, a springbeing pro--- vided tending to maintain said cam andl said arm in normal position and a further spring tending to maintain said pedal -in' normal position with respect to said arm..`

91' Brake operating means comprisinigv'brake applying means, Huid pressure operated,

brake'releasing means normally counteracting said brake applying means, manually v operated means controlling said fluid pressure operated means, andmean's for positively controlling the operation of said brake applying mea/ns in accordance with the operation of said` manually operated means.

In testimony whereof I have aixed my signature. o

MAUNSELL B. JACKSON. 

